Electrical charge relaxable wear resistant coating for bias charging or transfer member

Abstract

A bias transfer member or bias charging member for a xerographic device includes a support substrate, and a multi-layer conductive surface coating over the support substrate. The multi-layer coating includes a base layer of metal-containing particles in a polymer binder, an intermediate layer of conductive particles in a polymer binder, and a top layer of conductive particles in a polymer binder, wherein the amount of the conductive particles in the top layer is greater than the amount of the conductive particles in the intermediate layer. The multi-layer coating exhibits ideal electrical and abrasion resistance performance for use in bias charging or transfer members.

What is claimed is:  
     
       1. A bias transfer member or bias charging member comprising 
       a support substrate, and  
       a multi-layer conductive surface coating over the support substrate comprising a base layer comprised of metal-containing particles in a polymer binder, an intermediate layer comprised of conductive particles in a polymer binder, and a top layer comprised of conductive particles in a polymer binder, wherein the amount of the conductive particles in the top layer is greater than the amount of the conductive particles in the intermediate layer.  
     
     
       2. The bias transfer member or bias charging member according to  claim 1 , wherein the support substrate is in roll form and comprises a metal or a polymer with a metal surface coating. 
     
     
       3. The bias transfer member or bias charging member according to  claim 1 , wherein the support substrate further comprises a deformable layer between the support substrate and the multi-layer conductive surface coating. 
     
     
       4. The bias transfer member or bias charging member according to  claim 3 , wherein the deformable layer comprises a foam, an elastomer or a rubber. 
     
     
       5. The bias transfer member or bias charging member according to  claim 1 , wherein the polymer binder of each of the base layer, the intermediate layer and the top layer are the same or different, and are selected from the group consisting of polyurethanes, polyureas, polyolefins, polyesters, polyamides and mixtures or copolymers thereof. 
     
     
       6. The bias transfer member or bias charging member according to  claim 1 , wherein the metal-containing particles contain one or more metals of magnesium, tin and aluminum. 
     
     
       7. The bias transfer member or bias charging member according to  claim 1 , wherein the metal-containing particles of the base layer are spherical, rods or both. 
     
     
       8. The bias transfer member or bias charging member according to  claim 7 , wherein the spherical particles have an average volume diameter of about 10.0 microns or less and the rods have an average volume length of about 1.0 microns or less. 
     
     
       9. The bias transfer member or bias charging member according to  claim 7 , wherein the metal-containing particles contain one or more metals of magnesium, tin and aluminum. 
     
     
       10. The bias transfer member or bias charging member according to  claim 9 , wherein the metal-containing particles further contain at least one non-metal component. 
     
     
       11. The bias transfer member or bias charging member according to  claim 10 , wherein the non-metal component is silicon. 
     
     
       12. The bias transfer member or bias charging member according to  claim 11 , wherein the base layer contains metal-containing spherical particles comprised of magnesium, tin and silicon and contains metal-containing rods comprised of aluminum and silicon. 
     
     
       13. The bias transfer member or bias charging member according to  claim 1 , wherein the conductive particles of each of the intermediate layer and the top layer are the same or different, and are selected from the group consisting of carbon black and graphite. 
     
     
       14. The bias transfer member or bias charging member according to  claim 13 , wherein the conductive particles of both the intermediate layer and the top layer are carbon black. 
     
     
       15. The bias transfer member or bias charging member according to  claim 1 , wherein the top layer contains at least about 10% by weight of the conductive particles. 
     
     
       16. The bias transfer member or bias charging member according to  claim 1 , wherein the base layer has a thickness of about 75 microns or less, the intermediate layer has a thickness of about 100 microns or less and the top layer has a thickness of about 75 microns or less. 
     
     
       17. The bias transfer member or bias charging member according to  claim 1 , wherein the conductive surface coating has a total thickness of about 200 microns or less. 
     
     
       18. The bias transfer member or bias charging member according to  claim 1 , wherein the surface conductive coating has a relaxation time constant of from about 1 to about 10 milliseconds. 
     
     
       19. A xerographic device including at least one of a bias transfer member or a bias charging member according to  claim 1 .